draw outline for some connected lines

most problem cases are solved by translation vectors intersection check

• black is the original line/curve whatever …
• gray is translation vector (normal to black and size = outline distance)
• blue is outline

if the translation vectors not intersect then it is most likely all OK but if they do then just do something like this:

1. cut off these points from outline

2. or create some singular point from these intersections

   it is more tricky but can avoid some problem cases from bullet #1

Also sometimes help if there is bigger density of control points

Hope it helps a little…